The present invention relates to an inspection device to measure the bend angle of a formed component. The inventive machine uses a combined linear and rotational motion to measure numerous formed configurations.
Over the past years, manufacturers of bent tubular components have had a need to measure the bend angles produced on various bending machines. This is necessary for quality control. Good quality control can lead to good parts produced. The bend angle of a fabricated bent part is most often a critical aspect of a manufacturing process. Over the years, bend angles have been measured using many devices including dedicated fixtures, digital protractors, various four-bar linkages coupled to digital readouts, and optical techniques.
Dedicated fixtures are quick and accurate yet do not lend themselves well to being useful for measuring other bent configurations. Because of their dedicated nature, a dedicated measuring device is designed to measure only one configuration and thus is not intended to measure numerous configurations.
Digital protractors are accurate and can measure numerous shapes, yet do not lend themselves well to measuring bend angles as the bend angle approaches 180xc2x0. This is due to the fact that the pivot point on a commercial digital protractor is unable to transverse in a linear fashion and thus the range of useful motion is limited when attempting to measure numerous bent configurations.
There have been several digital devices coupled with various four-bar linkage designs to overcome the above disadvantages. Four-bar linkage devices intended to measure most bend angles are flexible to accommodate numerous tubular configuration. Nevertheless, four-bar linkages, by design, are constructed from several moving parts. With several moving parts in an inspection device, the repeatability of such a device will be limited. This limitation is caused by the excessive number of moving parts in contact with each other. Interaction between moving parts produce friction, and friction in an inspection machine leads to results that are not accurate and repeatable over time.
Optical techniques, as disclosed by Brinkman, et al., U.S. Pat. No. 6,268,912, require a vast amount of software and electronics to operate. These techniques are intended for the high end of the inspection market and do not address a low cost solution.
Accordingly, several objects and advantages of my invention are:
(a) to reduce the number of components in a bend-angle measuring machine;
(b) to market a digital bend-angle measuring machine at a low cost;
(c) to provide a bend-angle measuring machine that will quickly adjust to numerous bend angle configurations; and
(d) to provide a simple mechanism, with few moving components, to minimize the amount of friction in the measuring system.
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
The foregoing and other objects and advantages can be achieved by providing a fixed arm and a movable arm connected to a common base. The fixed arm is fixed relative to the base and the movable arm is able to transverse in a linear and rotational fashion toward and away from the movable arm. Coupled to the rotational motion of the movable arm is a digital encoder. The encoder transmits the position of the rotational axis of the movable arm to a digital readout and thus displays the rotational position (angle) of the movable arm relative to the fixed arm.